There is a widespread demand for relatively small valves which can operate reliably and quickly, using very little energy for actuation, and capable of lasting for many millions of cycles. While there are applications for such valves in many fields, there are special requirements in medical laboratories and in their analytical equipment. In these applications valves are opened frequently to pass various solutions, sometimes from two different sources to one destination, or sometimes from one source to one or the other of two destinations. Examples of liquids to be controlled are water, saline solution, and reagent solutions.
Often the quantity to be passed is quite small, so that a quick acting valve is necessary. Clearly it is desirable to keep the energy consumption and the heat produced by the valves to the lowest practical level. A valve according to this invention can operate on as little as 1.5 watts of power, and can open or close in 5 milliseconds.
Also, some instruments use many of these valves. It is very expensive and disruptive to find and replace individual valves which have failed in such instrumentation. Accordingly service life is of serious importance. A valve according to this invention can readily be made to operate for at least 20 million cycles without repair. Furthermore, the valve can be made so economically that replacement of the valve is a viable alternative to repair.